System and method for cardiac valve repair and replacement

ABSTRACT

A method of delivering a prosthetic mitral valve includes delivering a distal anchor from a delivery sheath such that the distal anchor self-expands inside a first heart chamber on a first side of the mitral valve annulus, pulling proximally on the distal anchor such that the distal anchor self-aligns within the mitral valve annulus and the distal anchor rests against tissue of the ventricular heart chamber, and delivering a proximal anchor from the delivery sheath to a second heart chamber on a second side of the mitral valve annulus such that the proximal anchor self-expands and moves towards the distal anchor to rest against tissue of the second heart chamber. The self-expansion of the proximal anchor captures tissue of the mitral valve annulus therebetween.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/170,407, filed on Jan. 31, 2014, entitled “SYSTEM AND METHOD FORCARDIAC VALVE REPAIR AND REPLACEMENT,” Publication No.US-2015-0025623-A1, which claims priority to U.S. Patent ProvisionalApplication No. 61/847,515, filed on Jul. 17, 2013, entitled “SYSTEM ANDMETHOD FOR CARDIAC VALVE REPAIR AND REPLACEMENT,” the entirety of whichis incorporated by reference herein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD OF INVENTION

The present invention relates generally to the treatment of cardiacvalve disorders, such as mitral valve replacement, using minimallyinvasive techniques.

BACKGROUND

The mitral valve lies between the left atrium and the left ventricle ofthe heart. Various diseases can affect the function of the mitral valve,including degenerative mitral valve disease and mitral valve prolapse.These diseases can cause mitral stenosis, in which the valve fails toopen fully and thereby obstructs blood flow, and/or mitralinsufficiency, in which the mitral valve is incompetent and blood flowspassively in the wrong direction.

Many patients with heart disease, such as problems with the mitralvalve, are intolerant of the trauma associated with open-heart surgery.Age or advanced illness may have impaired the patient's ability torecover from the injury of an open-heart procedure. Additionally, thehigh costs are associated with open-heart surgery and extra-corporealperfusion can make such procedures prohibitive.

Patients in need of cardiac valve repair or cardiac valve replacementcan be served by minimally invasive surgical techniques. In manyminimally invasive procedures, small devices are manipulated within thepatient's body under visualization from a live imaging source likeultrasound, fluoroscopy, or endoscopy. Minimally invasive cardiacprocedures are inherently less traumatic than open procedures and may beperformed without extra-corporeal perfusion, which carries a significantrisk of procedural complications.

Minimally invasive aortic valve replacement devices, such as theMedtronic Corevalve or the Edwards Sapien, deliver aortic valveprostheses through small tubes which may be positioned within the heartthrough the aorta via the femoral artery or through the apex of theheart. However, current cardiac valve prostheses are not designed tofunction effectively within the mitral valve. Further, current cardiacvalve prostheses delivered via a minimally invasive device are oftendifficult to place correctly within the native valve, difficult to matchin size to the native valve, and difficult to retrieve and replace ifinitially placed incorrectly.

Accordingly, it is desirable to have a mitral valve replacement thatsolves some or all of these problems.

SUMMARY OF THE DISCLOSURE

In general, in one embodiment, a prosthetic mitral valve includes aproximal anchor, a distal anchor, and a central portion therebetween.The proximal and distal anchors each include a first outer frame and asecond outer frame. The first outer frame includes a plurality of firstarcs joined together, and the second outer frame includes a plurality ofsecond arcs joined together. The plurality of first arcs are out ofphase relative to the plurality of second arcs.

This and other embodiments can include one or more of the followingfeatures. The first plurality of arcs can be movable relative to thesecond plurality of arcs. The first and second outer frames can besubstantially circular. The plurality of first arcs can be disposedaround substantially the entire first outer frame, and the plurality ofsecond arcs can be disposed around substantially the entire second outerframe. The plurality of first arcs can lie substantially in a firstplane, and the plurality of second arcs can lie substantially in anadjacent second plane. The first and second arcs can be approximately 90degrees out of phase. The first and second outer frames can be made ofwire rope. The wire rope of the first outer frame can have an oppositelay than a lay of the wire rope of the second outer frame. The proximalanchor and distal anchor can be substantially parallel to one another.The central portion can include substructures connecting the proximaland distal anchors. The substructures can be hexagonal. The proximalanchor, distal anchor, and central portion can be configured to expandfrom a constrained configuration to an expanded configuration. Thedevice can be configured to foreshorten upon expansion of the proximalanchor, distal anchor, and central portion from the constrainedconfiguration to the expanded configuration. The proximal anchor and thedistal anchor can each have a diameter in the expanded configurationthat is greater than a diameter of the central portion in the expandedconfiguration.

In general, in one embodiment, a prosthetic mitral valve includes avalve frame comprising a proximal anchor, a distal anchor, and a centralportion therebetween. The valve frame is configured to expand from aconstrained configuration to an expanded configuration. A plurality ofstruts is attached to the central portion and extends distally past thedistal anchor. A plurality of leaflets are secured to the plurality ofstruts such that at least a portion of each leaflet extends distallypast the distal anchor.

This and other embodiments can include one or more of the followingfeatures. The valve frame can be configured to self-expand. Theplurality of leaflets can be attached to the central portion. Theplurality of leaflets can include a biomaterial or a polymer. Theproximal anchor can be covered with a skirt configured to seal theprosthetic valve. The skirt can include a biomaterial or polymer. Theouter perimeter of the proximal anchor can be substantially circularwhen covered with the skirt. The plurality of leaflets can be arrangedto fill an inner diameter of the mitral valve prosthetic. The ratio ofthe inner diameter to a height of the plurality of struts can beapproximately 2:1. The valve frame can be configured to foreshorten uponexpansion of the valve frame from the constrained configuration to theexpanded configuration. The proximal anchor and the distal anchor caneach have a diameter in the expanded configuration that can be greaterthan a diameter of the central portion in the expanded configuration.

In general, in one embodiment, a prosthetic mitral valve includes avalve frame having a proximal anchor, a distal anchor, and a centralportion therebetween. The valve frame is configured to expand from aconstrained configuration to an expanded configuration. The ratio of anouter diameter of the central portion to a length of the valve frame inthe expanded configuration is at least 1.1.

This and other embodiments can include one or more of the followingfeatures. The valve frame can be configured to self-expand. The ratiocan be less than or equal to 2. The ratio of the outer diameter of theproximal anchor or the distal anchor to the length of the device can begreater than or equal to 2. The outer diameter of the central portioncan be between 25 and 40 mm. The length can be less than or equal to 22mm. The proximal and distal anchors can extend radially outward from thecentral portion. The outer diameter of the proximal and distal anchorscan be at least 38 mm.

In general, in one embodiment a method of delivering a prosthetic mitralvalve includes delivering a distal anchor from a delivery sheath suchthat the distal anchor self-expands inside a first heart chamber on afirst side of the mitral valve annulus, pulling proximally on the distalanchor such that the distal anchor self-aligns within the mitral valveannulus and the distal anchor rests against tissue of the ventricularheart chamber, and delivering a proximal anchor from the delivery sheathto a second heart chamber on a second side of the mitral valve annulussuch that the proximal anchor self-expands and moves towards the distalanchor to rest against tissue of the second heart chamber. Theself-expansion of the proximal anchor captures tissue of the mitralvalve annulus therebetween.

This and other embodiments can include one or more of the followingfeatures. The first heart chamber can be a ventricular heart chamber,and the second heart chamber can be an atrial heart chamber.

In general, in one embodiment, a method of delivering a prostheticmitral valve includes securing a prosthetic valve within a deliverydevice by extending a plurality of wires of the delivery device througha proximal anchor so as to collapse the proximal anchor, extending theprosthetic delivery device into a heart with the prosthetic valvecovered by a sheath of the delivery device, pulling the sheathproximally to expose a distal anchor of the prosthetic valve, therebyallowing the distal anchor to self-expand into place on a first side ofthe mitral valve annulus, pulling the sheath proximally to expose theproximal anchor, loosening the wires of the delivery device so as toallow the proximal anchor to self-expand into place on a second side ofthe mitral valve annulus, and removing the delivery device from theheart.

This and other embodiments can include one or more of the followingfeatures. The method can further include tightening the wires afterloosening the wires so as to collapse the proximal anchor again,repositioning the proximal anchor to a second location on the secondside of the mitral valve annulus and loosening the wires of the deliverydevice so as to allow the proximal anchor to self-expand into place atthe second location on the second side of the mitral valve annulus.Extending a plurality of wires of the delivery device through a proximalanchor so as to collapse the proximal anchor and can include extending aplurality of wires through arcs of the proximal anchor. Neighboringretention wires can extend through neighboring arcs. The method canfurther include extending a guidewire down a central lumen of thedelivery device before extending the prosthetic delivery device into theheart. Tightening and loosening the wires of the delivery device can beperformed with a control on a handle of the delivery device.

In general, in one embodiment, a delivery device includes a centrallongitudinal structure having a plurality of tubes extendingtherethrough, a retention wire extending within each tube, a sheath, ahandle, and a control on the handle. Each tube has a tubular wall and anaperture in the tubular wall. Each retention wire configured to extendthrough a portion of a medical device at the aperture. The sheath isconfigured to fit over and slide relative to the central longitudinalstructure and the medical device. The handle is connected to the centrallongitudinal structure. The control on the handle is configured totighten the wires to collapse at least a portion of the medical deviceand to loosen the wires to expand the portion of the medical device.

This and other embodiments can include one or more of the followingfeatures. The delivery device can further include a central lumenextending through the central longitudinal structure. The central lumencan be configured to house a guidewire. The retention wires can be madeof nitinol or liquid crystal polymer fiber. There can be between 4 and20 retention wires and tubes. The delivery device can further include atapered distal tip connected to the central longitudinal structure. Thecontrol can be further configured to retighten the wires after looseningto collapse the portion of the medical device again.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims. A better understanding of the features and advantages of thepresent invention will be obtained by reference to the followingdetailed description that sets forth illustrative embodiments, in whichthe principles of the invention are utilized, and the accompanyingdrawings of which:

FIGS. 1A-1E are various view of a compliant, self-centering valveprosthesis structure suitable for delivery via minimally invasivesurgical techniques. FIGS. 1A and 1B are isometric views of theprosthesis. FIG. 1C is a proximal view of a proximal anchor of theprosthesis. FIG. 1D is a proximal view of the prosthesis. FIG. 1E is aside view of the prosthesis.

FIGS. 2A-2C show an exemplary prosthesis with leaflets attached thereto.FIG. 2A is an isometric view of the prosthesis. FIG. 2B is a distal viewof the prosthesis. FIG. 2C is a section view of the prosthesis.

FIGS. 3A-3B show the prosthesis of FIGS. 1A-1E with various dimensionsmarked thereon. FIG. 3A is a proximal view of the prosthesis. FIG. 3B isa side view of the prosthesis.

FIG. 4A shows a delivery device with a prosthesis fully loaded therein.

FIG. 4B shows the delivery device with the prosthesis deployed.

FIGS. 5A-5D shows exemplary steps for delivery a valve prosthesis. FIG.5A shows a delivery device housing the prosthesis. FIG. 5B shows thedistal anchor of the prosthesis deployed with the proximal anchor foldedup therearound. FIG. 5C shows the sheath of the delivery device pulledback to expose the retention wires of the delivery device. FIG. 5D showsthe valve prosthesis fully deployed around the delivery device.

FIGS. 6A-6D show placement of a prosthesis within the mitral valve usinga delivery device.

FIG. 7 shows a valve prosthesis structure with integral folding hooksfor gripping cardiac tissue.

FIGS. 8A-8B and 9A-9B show various wire rope configurations.

FIGS. 10A-10B show a mechanism for releasing the retention wires of adelivery device by pulling proximally on the retention wires.

FIGS. 11A-11B show a mechanism for loosening the retention wires of adelivery device by pushing distally on the retention wires.

FIGS. 12A-12B show an exemplary mechanism for looping the proximalanchor with the retention wires of a delivery device. FIG. 12A shows theuse of twelve retention wires. FIG. 12B shows the use of six retentionwires.

FIG. 13 shows an alternative mechanism for looping the proximal anchorover a delivery device.

DETAILED DESCRIPTION

Described herein is a flexible, self-orienting cardiac valve prosthesisconfigured to be delivered through minimally invasive techniques. Theprosthesis can include a proximal anchor (e.g., configured to be placedin the ventricle), a distal anchor (e.g., configured to be placed in theatrium), a central portion or column between the anchors, a plurality ofstruts extending distally (e.g., into the ventricle), and a plurality ofleaflets attached to the struts. The prosthesis can be self-expanding,such as be made of super elastic nickel titanium (nitinol). In someembodiments, the prosthesis can be made of woven stranded nitinol.

The prosthesis described herein can be delivered to a cardiac valveorifice, such as the mitral valve, by using minimally invasivetechniques to access cardiac valves through small incisions in thepatient's body, passing the prosthesis through the apex of the heart,through the aorta via femoral artery access, through the aorta via anintercostal puncture, through the vena cava via femoral vein access,through the vena cava via jugular access, and through the venous systeminto the left heart via a transseptal puncture. The flexible prosthesiscan be folded and compressed to fit within a delivery tube. The deliverytube can used to position the prosthesis at the treatment site, and ifnecessary, re-sheath, reposition, and re-deploy the device.

During deployment, the distal anchor can be deployed first in a cardiacchamber, such as the ventricle, and retracted to a seated positionagainst the valve orifice, such as the mitral valve orifice. Then thecenter column and proximal anchor may then be deployed in anothercardiac chamber, such as the atrium, sandwiching the valve orificesecurely between the anchors in opposing cardiac chambers.

Embodiments of the invention are designed to secure the valve prosthesisin the orifice by applying a radial force from the center columnstructure of the prosthesis outward against the cardiac orifice and bysandwiching the cardiac orifice between distal and proximal anchors thatare larger in diameter than the orifice. Further engagement between theprosthesis and tissue may be added by securing small, curved wire hooksinto the sub-structures of the valve prosthesis.

FIGS. 1A-1E show an exemplary embodiment of a valve prosthesis 100. Thevalve prosthesis includes a proximal anchor 2, a distal anchor 3, and acentral portion 4 therebetween. A central opening 15 extends through thecenter of the prosthesis 100. The central portion 4 can substantiallytrace the perimeter of the central opening 15 while each anchor 2, 3 canextend outwardly therefrom in an annular shape. The proximal anchor 2,distal anchor 3, and central portion 4 can be formed of wire, such asnitinol wire rope. Each anchor 2,3 can include a first outer frame 122,133 and a second outer frame 222, 233, respectively. In one embodiment,the proximal anchor 2 and distal anchor 3 can be substantially parallelto one another.

An exemplary proximal anchor 2 is shown in FIG. 1C. The first outerframe 122 can sit proximal to the second outer frame 222, and the firstouter frame 122 can sit in a plane substantially parallel to the planeof the second outer frame 222. Further, each frame 122, 222 can includea plurality of arcs 111, 211 (which can also be referred to as arcuateportions, curved portions, or petals), such as between 4 and 10 orbetween 5 and 8 arcs, joined together at joints 16, 26, respectively.For example, outer frame 122 can include six arcs 111 a,b,c,d,e,f whileouter frame 222 can also include six arcs 211 a,b,c,d,e,f. The arcs 111of the outer frame 122 can be connected together, and the arcs 211 ofthe outer frame 222 can be connected together, so as to form asubstantially circular outer perimeter for each of the frames 122, 222.

Each joint 16, 26 between neighboring arcs 111 or 211 can be, forexample, a crimp that crimps adjacent arcs (e.g., 111 a and 111 b) toone another. As shown in FIG. 1C, the outer frames 122, 222 can bepositioned relative to one another such that the arcs 111, 211 are outof phase relative to one another. For example, the arcs 111 can beapproximately 90 degrees out of phase relative to the arcs 211. That is,the arcs 111 of the first outer frame 122 can overlap with the arcs 211of the second outer frame 222 such that, for example, a single arc 111 aof the first outer frame 122 overlaps with half of two underlying arcs211 f, 211 a of the second outer frame 222. In some embodiments, onlysome arcs are out of phase with one another while other arcs arein-phase with one another. The second outer frames 133, 233 can likewiseinclude arcs as described with respect to the first outer frame 122,222.

As shown in FIGS. 1A and 1E, the first outer frame 122, 133 and thesecond outer frame 222, 233 of each anchor 2, 3 can be connected to oneanother through the central portion 4. The central portion 4 can extendfrom the crimps 16, 26 of the proximal anchor 2 to the correspondingcrimps of the distal anchor 3. The central portion 4 can includesubstructures or wire segments 44 that form a pattern, such as ahexagonal pattern (see FIG. 1E). For example, two wire segments 44 a,bof the central portion 4 can extend at an angle from the crimp 16 a (seeFIGS. 1D, 1E), such as to form an angle of approximately 120 degreesrelative to one another. Each of the wire segments 44 a,b can then meetadjacent wire segments within the central portion 4 (e.g., segment 44 bmeets segment 44 c). The adjacent wire segments (e.g., 44 b and 44 c)can then be joined together at a joint 46 (e.g., joint 46 a). The joint46 a can form a column substantially parallel to a central axis 110 ofthe prosthesis 100. This pattern can extend throughout the entireprosthesis to form a number of joints 46, such as twelve joints 46. Thejoints 46 can not only fix the position of the outer frames of a singleanchor together, but also fix the proximal and distal anchors 2, 3together. The hexagonal structure of the segments 44 and joints 46 canadvantageously provide radial and vertical strength as well as stabilityto the prosthesis 100.

In some embodiments (as shown in FIG. 1D), parts of the central portion4 can be formed of the same wire or wire rope as the outer frames of theanchors 2,3 and/or the outer frames of the anchors 2,3 can be formed ofthe same wire or wire rope as one another. For example, two singlestrands of wire, such as two 22-inch long strands of wire, can be usedto form the anchors 2, 3 and the central portion 4. As shown in FIGS. 1Dand 1E, a single strand 191 (darkened in the picture relative to theopposite strand 193 for clarity) can form an arc 111 a (see FIG. 1D) ofthe first outer frame 122 of proximal anchor 2, extend through a joint16 a to form wire segment 44 b of the central portion 4, extend throughjoint 46 a to form wire segment 44 d (see FIG. 1D), then form an arch ofthe second outer frame 233, extend through another joint to form wiresegment 44 e (see FIG. 1D), extend around in a similar fashion to formwire segment 44 f (see FIG. 1D), and continue winding in a similarfashion until all of the outer frames 122, 233 have been formed from thesingle strand 191. The ends of the strand 191 can then be attached toone another, such as through splicing crimps, butt joint crimps,welding, riveting, or weaving. The second strand 193 can be woundsimilarly to form the second outer frame 222 of the proximal anchor 2and the first outer frame 133 of the distal anchor 3.

By joining the first outer frame 122, 133 to the second outer frame 222,233 of each anchor 2, 3, as described above, the arcs of each outerframe can be movable relative to one another. For example, the arc 111 acan be movable relative to the arcs 211 f, 211 a that it overlaps (seeFIG. 1C). That is, the outer perimeter of the arc 111 a can flex alongthe central axis and/or translate relative to the arcs 211 f, 211 a(while the inner perimeter is fixed at the joints 46).

Advantageously, the large arc structure of the anchors can provideflexibility and compliance for the portions of the prosthesis intendedto be placed in the chambers of the heart. In contrast, in the stiffertissue of the valve orifice, the hexagonal sub-structures of the centralportion can provide higher radial stiffness and strength.

Further, by using wire rope, the prosthesis can advantageously befoldable and strong while the individual fibers, because they are smallin diameter, can maintain resistance to fatigue and fracture. In someembodiments, the two frames of a single anchor can be formed of wirerope of opposite lays. For example, the wire of one frame (e.g. strand193) can be made of a rope twisted to the left while the wire of anotherframe (e.g. strand 191) can be made of a rope twisted to the right.Using wires of opposite lays can allow the wires to compensate for oneanother as they compress, thereby maintaining relative positioningduring expansion or contraction/folding of the device (as opposed totwisting of the entire device). Various possibilities for winding thewire rope are shown in FIGS. 8A-9B.

As shown in FIGS. 1A and 1E, struts 5 can extend distally from thedistal anchor 3 and/or the central portion 4 and be configured to holdleaflets (shown in FIGS. 2A-2C). The struts 5 can be formed, forexample, of wire rope. Further, in one example, each strut 5 can includea plurality of wire components 55, such as three wire components 55.Each of the three wire components 55 of a single strut 5 can extend fromneighboring joints 46 and come together at a joint 56, thereby formingtriangular struts 5. In some embodiments, additional supportingstructures, such as tubes, can be placed over or around the struts toincrease the stiffness. The triangular struts 5 can provide verticalstrength and lateral flexibility.

In one embodiment, there can be three struts 5 located approximately 120degrees away from one another around the circumference of the prosthesis100. The joints 56 can be, for example, crimps. As shown in FIGS. 1A and1E, in one embodiment, the center strut member 55 a of a three-strutsupport can be substantially straight and connected to two outside,curved strut members 55 b, 55 c to form a structure comprised of twosubstantially triangular sub-structures, each with the center member asa common triangle leg. This center member may be made of a thin elementof material which provides strength in tension as the pressurizedleaflets are pushed toward the center of the valve, while providingflexion in compression to allow the valve prosthesis to be folded fordelivery and to allow the prosthesis to conform to tissue when placedwithin the heart.

The various crimps used for the joints of the prosthesis 100 may be madeof a suitable implantable material, such as platinum, tantalum, ortitanium. Further, in place of crimps, braids, weaves, or welding can beused.

Referring to FIGS. 2A-2C, the valve prosthesis 100 can include integralvalve leaflets 511 attached, such as sewn, to the struts 5. There can bethree integral valve leaflets 511, and the leaflets 511 can form apressure actuated valve that provides uni-directional flow occlusionwhen the prosthesis 100 is implanted in a valve orifice. The leafletscan be constructed of bio-materials, such as bovine or porcinepericardium, or polymer materials.

In one embodiment (shown in FIGS. 2B-2C), the proximal anchor 2 caninclude a cover or skirt 12 thereon or therearound formed of abiomaterial or thin polymer material. The skirt 12 can advantageouslyhelp seal the prosthesis 100 against the cardiac tissue when implanted.

The prosthesis 100 can be configured to be placed in a cardiac valveorifice such that the central portion 4 lines the orifice while theproximal and distal anchors 2, 3 sit within the chambers of the heartand pinch tissue of the orifice therebetween.

In some embodiments, the prosthesis 100 can be sized and configured foruse in the mitral valve orifice (shown in FIG. 6D). Referring to FIGS.3A-3B, to ensure that the prosthesis 100 fits properly within the valve,the diameter d_(o) of the central opening 15 can be greater than alength l of the device when fully expanded. For example, the ratiod_(o)/l can be greater than or equal to 1.1, such as greater than orequal to 1.2 or greater than or equal to 1.3. Further, the ratio d_(o)/lcan be less than 2.0. In one embodiment, the diameter d_(o) is between25 mm and 40 mm, such as approximately 28 mm. Further, in oneembodiment, the length l is less than or equal to 22 mm, or less than orequal to 20 mm, such as approximately 14 mm. Further, to ensure that theproximal and distal anchors have enough tissue to grab onto, a ratio ofthe outer diameter of the anchors, d_(T), to the length l can be greaterthan or equal to 2.0. In one embodiment, an outer diameter of anchors,d_(T), can be at least 38 mm, such as greater than or equal to 40 mm.Further, in one embodiment, the anchors can extend out at a radius r_(a)of greater than 10 mm, such as approximately 12 mm. Finally, a ratiod_(o) to a length of the struts l_(s) can be approximately 1.5 to 3.0,such as 2.1. A radio of d_(o)/l_(s) within this range can advantageouslyensure that there is enough leaflet material to allow the leaflets tooppose and seal under stress while maintaining a small enough length tofit properly within the valve. In one embodiment, the struts have alength l_(s) of between 8 and 16 mm, such as approximately 14 mm.Further, l_(c) can be approximately 4-10 mm, such as 6 mm.

In one exemplary embodiment, d_(o) is 28 mm, r_(a) is 12 mm, l_(c) is 6mm, l_(s) is 14 mm, d_(T) is 40 mm, and l1 is 14 mm.

FIGS. 4A-4B show a closed delivery device 200 for delivery of a valveprosthesis 100. The delivery device 200 can include an outer sheath 13and a multi-lumen central longitudinal structure 17 extendingtherethrough. The valve prosthesis 100 is configured to fit over thecentral longitudinal structure 17 and within the sheath 13 so as to befully encapsulated within the delivery device 200. The lumens in thelongitudinal structure 17 can be tubular structures 357 (see FIGS. 4Band 5C). Each tubular structure 357 can include a side lumen 355 (seeFIGS. 4B and 10A) therein, i.e, an aperture disposed on a radial outerportion of the tubular wall. The tubular structures 357 can containretention members 19 that bind the proximal anchor 2 of the valveprosthesis tightly to the longitudinal structure 17. The retentionmembers 19 can be made, for example, of a strong, flexible material suchas nitinol, nitinol wire rope, or liquid crystal polymer fiber, such asVectran®. There can be various numbers of retention wires andcorresponding tubes 357 and lumens, such as between 4 and 20 or between6 and 12 retention wires and corresponding tubes/lumens. In oneembodiment, there are six retention wires and lumens. In another, thereare twelve retention wires and lumens. The delivery device 200 includesa central lumen 15 running therethrough (i.e., through the centrallongitudinal structure 17) configured to pass a standard cardiacguidewire 16. The guidewire 16 may be used to provide a safe pathway forgetting the device 100 to the anatomical target. The delivery device 200further includes a tapered tip 14 to provide a gradual, atraumatictransition from the guidewire to the outer sheath 13 of the deliverydevice 200.

In some embodiments, the delivery device 200 can be adapted to specificdelivery paths and cardiac structures by being provided with pre-shapedbends in the outer sheath 13. In some embodiments, the delivery device200 may contain pull-wires integral with the outer wall that may betensioned to articulate and bend the outer sheath 13. The pull wires mayterminate at the tip of the device to provide a bend starting at thedistal tip or may terminate along the longitudinal shaft of the deviceto provide a more proximal bend location.

FIGS. 5A-5D show a multi-stage delivery system for a cardiac valveprosthesis (with the valve leaflets omitted from the drawings forclarity). FIG. 5A shows the delivery device 200 having a handle 300connected thereto to control the delivery of a prosthesis loaded withinthe device.

FIGS. 5B and 5C shows the prosthesis 100 partially deployed. That is, asthe sheath 13 is pulled back with a lever 301 on the handle 300, thedistal anchor 3 (previously collapsed into the sheath 11 with the peaksof the arcs extending distally) pops open. The proximal anchor 2, inturn, can remain connected to the delivery device 100 via the retentionwires 19. That is, the retention wires 19 can pass through themulti-lumen central structure 17, through the arcs of the outer frame122, 222 at apertures 355, and back into lumens of the structure 17.Referring to FIGS. 10A and 12A, in one embodiment, the proximal anchor 2can be connected to the retention wires 19 such that neighboring arcs111 a, 211 a of the proximal anchor 2 extend over neighboring retentionwires 19 a, 19 b. In other embodiments (as shown in FIG. 12B), twoneighboring arcs 111 a, 211 a can extend over a single retention wire 19a. Referring back to FIGS. 5B and 5C, as the retention wires 19 arepulled tight, the peaks of the arcs of the proximal anchor 2 will bepulled proximally, thereby causing the proximal anchor 2 to fold orcinch up to form a funnel shape at the proximal end of the distal anchor3 (crimps 16, 26 of the proximal anchor 2 can be seen).

To expand the proximal anchor 2, the wires 19 can either be withdrawn orloosened (such as with a lever 303 on the handle), thereby allowing theproximal anchor 2 to self-expand into place, as shown in FIG. 5D.Referring to FIGS. 10A-10B, in some embodiments, the wires 19 a can bewithdrawn completely, thereby allowing the proximal anchor 2 to expand.In another embodiment, shown in FIGS. 11A-11B, the retention wires 19can be formed of loops that, when loosened, i.e. pushed distally, allowthe distal anchor 2 to expand without releasing the anchor 2. By usingsuch a mechanism, the proximal anchor can be resheathed and moved (byretightening the retention members 19) if necessary. A mechanism on thehandle can then be used to release the retention members 19 entirely.

Referring to FIG. 6A, to deploy the valve prosthesis 100 in a valve(such as the mitral valve), the guidewire 16 and delivery device 200 canbe inserted through the native valve. Referring to FIG. 6B, as the outersheath 13 of the device 200 is retracted relative to the centrallongitudinal structure 17, the distal anchor 3 of the valve prosthesisis exposed and self-expands (such as into the left ventricle). Onceexpanded, the distal anchor 3 may be retracted proximally against thedistal-facing tissue of the cardiac chamber around the orifice,providing positive tactile feedback that the distal anchor 3 is orientedand positioned properly against the distal wall of the cardiac orifice.Further retraction of the sheath 13 exposes the central portion 4 of thevalve prosthesis, allowing the central portion 4 to radially expandagainst the inner wall of the cardiac orifice.

Referring to FIG. 6C, to expand the prosthesis 100 on the other side ofthe cardiac orifice (i.e., in the left atrium), the central retentionmembers 19 of the delivery device can be withdrawn or loosened asdescribed above, thereby expanding the proximal anchor 2. The expandedproximal anchor 2 provides a second backstop to the valve prosthesis100, allowing the prosthesis 100 to sandwich the valve orifice, such asthe mitral valve orifice between the proximal and distal anchors 2, 3.As the device 100 expands, it foreshortens, moving the proximal anchor 2and distal anchor 3 toward each other to provide a compressive force ontissue surrounding the cardiac orifice, such as the valve annulus.

Thus, in one example, as shown in FIG. 6D, the prosthesis can bedelivered into the mitral valve orifice such that the distal anchor 3sits within the left ventricle while the proximal anchor 2 sits withinthe left atrium. The struts 5 and leaflets 511 can extend distally intothe left ventricle. Tissue of the mitral valve annulus can be capturedbetween the anchors 2, 3. Further, the size of the prosthesis 100 can besuch that the anchors 2, 3 extend within the chambers of the heart andmuch wider than the diameter of the orifice itself, thereby allowing forstrong tissue capture and anchoring. In some embodiments, placement ofthe prosthesis can move the existing leaflets valves out of the way.

In some embodiments, as described above, the valve prosthesis 100 can berepositioned using the delivery device 200. That is, by pulling on theretention wires 19, the proximal anchor 2 can be cinched back down withthe proximal arcs extending proximally. The distal anchor 3 can becollapsed into the sheath (with the arcs extending distally) either bypulling proximally on the prosthesis 100 or pushing the sheath 13distally.

Use of an alternative delivery device is shown in FIG. 13. As shown inFIG. 13, rather than including multiple retention wires, the deliverydevice can include a single elongate member 96 over which all of thearcs 111, 211 of the proximal anchor 2 are placed.

FIG. 7 shows an embodiment of the valve prosthesis 199 where retentionhooks 21 are built into the device. The hooks 21 extend from toward thecenter of the device from the joints (e.g., crimps) of the distal anchor3. The hooks may be made of nitinol and are curved so that as the distalanchor 3 is drawn toward the center longitudinal member 17 of thedelivery device 200, the hooks flatten and collapse, allowing the outersheath 13 of the delivery device 200 to slide smoothly over the hooks21. As the outer sheath 13 is removed from the valve prosthesis 100during delivery and the distal anchor 3 of the valve prosthesis opens,the hooks 21 expand into the tissue of the cardiac orifice. Inembodiment, the hooks 21 are only located on the distal anchor 3, as thedistal anchor 3, when located on the ventricular side of the aorta,undergoes the highest pressure. In other embodiments, the hooks 21 arelocated on the proximal anchor 2 and/or the central portion 4.

In one embodiment, small hooks in the distal anchor 3 may be used togrip the valve leaflets. As the distal anchor 3 is retracted from theventricle toward the mitral valve annulus, the hooks can pull theleaflets into a folded position just under the ventricular side of themitral annulus.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A prosthetic mitral valve comprising: an anchorassembly comprising a ventricular anchor, a central portion, and anatrial anchor, wherein the ventricular anchor and the atrial anchor areboth formed of a plurality of arcuate portions, the anchor assemblyconfigured to self-expand from a collapsed configuration to an expandedconfiguration, the anchor assembly configured to foreshorten whenself-expanding from the collapsed configuration to the expandedconfiguration such that the prosthetic mitral valve obtains an expandedlength L that is less than a length of the prosthetic mitral valve inthe collapsed configuration, further wherein the ventricular anchor andthe atrial anchor are configured to flare outward relative to thecentral portion when self-expanding from the collapsed configuration tothe expanded configuration such that the prosthetic mitral valve obtainsan outermost diameter D that is greater than an outermost diameter ofthe prosthetic mitral valve in the collapsed configuration; and aplurality of replacement leaflets secured to the anchor assembly;wherein a ratio of D to L is greater than or equal to
 2. 2. Theprosthetic mitral valve of claim 1, wherein the plurality of leafletscomprise a biomaterial.
 3. The prosthetic mitral valve of claim 1,wherein at least a portion of the anchor assembly is covered with askirt configured to seal the prosthetic mitral valve during use.
 4. Theprosthetic mitral valve of claim 1, wherein the plurality of leafletsare arranged to fill an inner diameter of the prosthetic mitral valve.5. A prosthetic mitral valve comprising: an anchor assembly comprising aventricular anchor, a central portion, and an atrial anchor, the anchorassembly configured to self-expand from a collapsed configuration to anexpanded configuration, the anchor assembly configured to foreshortenwhen self-expanding from the collapsed configuration to the expandedconfiguration such that the prosthetic mitral valve obtains an expandedlength L that is less than a length of the prosthetic mitral valve inthe collapsed configuration, further wherein the ventricular anchor andthe atrial anchor are configured to flare outward relative to thecentral portion when self-expanding from the collapsed configuration tothe expanded configuration such that the prosthetic mitral valve obtainsan outermost diameter D that is greater than an outermost diameter ofthe prosthetic mitral valve in the collapsed configuration; a pluralityof replacement leaflets secured to the anchor assembly; and a pluralityof struts attached to the anchor assembly and extending distally pastthe ventricular anchor when the anchor assembly is in the expandedconfiguration, the plurality of leaflets secured to the anchor assemblywith the plurality of struts; wherein a ratio of D to L is greater thanor equal to
 2. 6. The prosthetic mitral valve of claim 5, wherein aratio of an inner diameter of the central portion to a length of theplurality of struts is approximately 1.1 or greater.
 7. The prostheticmitral valve of claim 5, wherein the ratio of an inner diameter of thecentral portion to the length of the plurality of struts isapproximately 1.3 or greater.
 8. The prosthetic mitral valve of claim 5,wherein the plurality of struts includes three struts, the three strutslocated approximately 120 degrees away from one another.
 9. A prostheticmitral valve comprising: an anchor assembly comprising a ventricularanchor, a central portion, and an atrial anchor, wherein the centralportion has a segment that extends substantially parallel to alongitudinal axis of the prosthetic mitral valve, the anchor assemblyconfigured to self-expand from a collapsed configuration to an expandedconfiguration, the anchor assembly configured to foreshorten whenself-expanding from the collapsed configuration to the expandedconfiguration such that the prosthetic mitral valve obtains an expandedlength L that is less than a length of the prosthetic mitral valve inthe collapsed configuration, further wherein the ventricular anchor andthe atrial anchor are configured to flare outward relative to thecentral portion when self-expanding from the collapsed configuration tothe expanded configuration such that the prosthetic mitral valve obtainsan outermost diameter D that is greater than an outermost diameter ofthe prosthetic mitral valve in the collapsed configuration; and aplurality of replacement leaflets secured to the anchor assembly;wherein a ratio of D to L is greater than or equal to
 2. 10. Theprosthetic mitral valve of claim 1, further comprising a plurality ofretention hooks attached to the anchor assembly.
 11. The prostheticmitral valve of claim 10, wherein the plurality of retention hooks areattached only to the ventricular anchor.
 12. A prosthetic mitral valvecomprising: an anchor assembly comprising a ventricular anchor, acentral portion, and an atrial anchor, the anchor assembly configured toself-expand from a collapsed configuration to an expanded configuration,the anchor assembly configured to foreshorten when self-expanding fromthe collapsed configuration to the expanded configuration such that theprosthetic mitral valve obtains an expanded length L that is less than alength of the prosthetic mitral valve in the collapsed configuration,further wherein the ventricular anchor and the atrial anchor areconfigured to flare outward relative to the central portion whenself-expanding from the collapsed configuration to the expandedconfiguration such that the prosthetic mitral valve obtains an outermostdiameter D that is greater than an outermost diameter of the prostheticmitral valve in the collapsed configuration; a plurality of replacementleaflets secured to the anchor assembly; and a plurality of retentionhooks attached to the anchor assembly, wherein the plurality ofretention hooks are curved such that, when the anchor assembly is in thecollapsed configuration, the hooks flatten and collapse, and when theanchor assembly is in the expanded configuration, the hooks extendoutwards; and wherein a ratio of D to L is greater than or equal to 2.13. The prosthetic mitral valve of claim 1, further comprising aplurality of struts attached to the anchor assembly and extendingdistally past the ventricular anchor when the anchor assembly is in theexpanded configuration, the plurality of leaflets secured to the anchorassembly with the plurality of struts.
 14. The prosthetic mitral valveof claim 1, wherein the central portion has a segment that extendssubstantially parallel to a longitudinal axis of the prosthetic mitralvalve.
 15. The prosthetic mitral valve of claim 5, wherein at least aportion of the anchor assembly is covered with a skirt configured toseal the prosthetic mitral valve during use.
 16. The prosthetic mitralvalve of claim 5, wherein the central portion has a segment that extendssubstantially parallel to a longitudinal axis of the prosthetic mitralvalve.
 17. The prosthetic mitral valve of claim 5, further comprising aplurality of retention hooks attached to the anchor assembly.
 18. Theprosthetic mitral valve of claim 17, wherein the plurality of retentionhooks are attached only to the ventricular anchor.
 19. The prostheticmitral valve of claim 9, wherein at least a portion of the anchorassembly is covered with a skirt configured to seal the prostheticmitral valve during use.
 20. The prosthetic mitral valve of claim 9,further comprising a plurality of retention hooks attached to the anchorassembly.
 21. The prosthetic mitral valve of claim 20, wherein theplurality of retention hooks are attached only to the ventricularanchor.